Thermoplastic shielded glass bottle

ABSTRACT

A container comprising an inner glass receptacle and a closely adhereing exterior protective sheath substantially covering said receptacle. The exterior protective is comprised of a shaperetaining, preferably thermoplastic resin adapted to restrain and retain glass fragments should the glass receptacle be broken. The sheath is further provided with a plurality of outwardly protruding nodular means that lend a roughened appearance to the sheath surface and which produce a surface elevation variance from the mean thickness of the sheath by between about 6 and 60 percent. This surface characteristic minimizes the container surface frictional resistance, increases shock resistance and provides maximum non-slip characteristics to the sheath when the container is hand-held.

United States Patent [191 Campagna [451 July 23, 1974 1 THERMOPLASTICSHIELDED GLASS BOTTLE [73] Assignee: Dart Industries Inc., Los Angeles,

Calif.

[22] Filed: Mar. 7, 1972 [21] Appl. No.: 232,412

Related U.S. Application Data [63] Continuation-impart of Ser. No.162,103, July 13,

[52] U.S. Cl. 215/1 C, 215/12 R, 21S/D1G. 6 [51] Int. Cl B65d 23/08 [58]Field 01' Search... 215/1 R, 1 C, 12 R, DIG. 6;l61/2,l16,117,119,124,164;117/l7.5,

3,200,280 8/1965 Th8 et a1 117/41 3,513,970 5/1970 Eckholm, Jr. 206/65 EFOREIGN PATENTS 0R APPLICATIONS 2,026,909 12/1970 Germany 215/1310. 6

Primary Examiner-William 1. Price Assistant ExaminerStephen Marcus [57]ABSTRACT A container comprising an inner glass receptacle and a closelyadhereing exterior protective sheath substantially covering saidreceptacle. The exterior protective is comprised of a shape-retaining,preferably thermoplastic resin adapted to restrain and retain glassfragments should the glass receptacle be broken. The sheath is furtherprovided with a plurality of outwardly protruding nodular means thatlend a roughened appearance to the sheath surface and which produce asurface elevation variance from the mean thickness of the sheath bybetween about 6 and 60 percent. This surface characteristic minimizesthe container surface frictional resistance, increases shock resistanceand provides maximum non-slip characteristics to the sheath when thecontainer is hand-held.

3 Claims, 3 Drawing Figures PATENTEU JULZ 3 I974 FIG.1

THERMOPLASTIC SHIELDED GLASS BOTTLE CROSS REFERENCES TO RELATEDAPPLICATIONS This is a continuation in part of my earlier applicationSer. No. 162.103 filed July 13, l97l.

This invention concerns protectively sheathed glassware containers and,more particularly, concerns glass receptacles which are so protected byan outer plastic envelope that substantially covers the exterior surfacethereof.

As is well known in the trade, glassware is readily susceptable tobreakage during handling and use. Further, the consequences of suchbreakage may be significantly aggravated if the contained product iscarbonated or the container thereof is otherwise internally pressurized.Therefore, it has long been an objective of glassware manufacturers andusers to minimize the hazards of breakage by treating the exteriorsurface in numerous ways and by even adding protective overcoatings ofvarious sorts thereto. These prior art approaches have, in fact,improved glassware standards and quality quite significantly since suchhave tended to effectively reduce the quantity of surface scratches andflaws in the ware and, of course, this reduction in the points of stressconcentration enable the ware to retain its characteristic strengthvSuch prior art surface treatments, for example, have included metaloxide, and combinations of thin film polyethylene coatings which providegood scratch and abrasion resistance to glassware thereby decreasing thesurface flaws spoken of and likewise reducing the likelihood ofbreakage. Similarly, protective coatings having substantial thicknesseshave been known for use on glass products. These, however, have beenapplicable only to specialized containers, for example, those employedin aerosol spray-type applications. Increased costs, productioninefficiencies in capably coating ware in the quantities required,providing a coating of the quality capable of restraining and retainingglass upon fragmentation under pressure, and employment of such ware inconventional filling and handling equipment have theretofore beenthought to make impossible the fruitful addition to the market ofcomposite glass, plastic-protected ware.

Specific problems presented and overcome by this invention have been toprovide the ware with a protective sheath or outer envelope of asufficient thickness and resiliency to adequately restrain and retainthe glass receptacle portion of a pressurized container againstfragmentation. To economically accomplish this end, the volume ofcoating material must be minimized, yet the effective thickness thereofmust be maximized to render the needed protection. Similarly, aconsistantly uniform, proper and good adhesion should be maintainedbetween the glass receptacle portion and sheath portion of the containerto provide the proper restraining effects. Additionally, in order forplastic coated ware to be easily processed in conventional equipment,exterior surface coefficients of friction must be minimized, yet thatsame surface should effectively produce a high coefficient when thecoated container is hand held. Both of these diametrically opposedpropositions (i.e., minimum material yet maximum protection and low yethigh coefficients of friction) are satisfied by the novel constructionof this invention.

In accordance with this invention, a novel container capable of internalpressurization is provided which has an inner glass receptacle orenvelope and a closely adhering outer sheath or envelope whichsubstantially covers the inner glass receptacle. The exterior protectivesheath comprises a shape-retaining, flexible resin which is able torestrain and retain fragments of the glass receptacle if the receptaclebreaks.

The exterior sheath is further provided with a plurality of outwardlyprotruding nodular means, nodal areas or nodes that minimize the surfacefrictional characteristics between abuting bottles and in mechanicalhandling, are shock absorbent, and due to its stippled effect, providemaximum non-slip characteristics when hand-held.

However, the nodal areas provide the noted increased shock protectionwhile employing a minimum of resin material. Such result is obtained dueto an increase in thickness at the nodular areas which will bear thebrunt of any physical abuse to which the container is subjected.Similarly, substantial portions of the coating are of a reducedthickness thus providing a material saving and creating voids into whichportions of the material forming the nodes may flow upon impact. Thus,the effective thickness of the resin sheath is that of the nodal areasand the necessity of providing a uniform overall coating thickness whichwould employ substantially more resin is avoided.

The nodes likewise reduce the area of contact exposed for example,between container surface to surface contact or contact betweencontainers and equipment since, in general, only the nodular surfaceareas will be in contact, thus, the frictional resistance therebetweenwill be reduced. At the same time, the nodes characteristicly provide amaximum non-slip effect when the container is hand-held, since theflexible supple surface of the human fingers conforms to the nodular orstippled, knurled-like surface of the container and contacts both thesurface of the nodes and the surface of the depressions, effectivelyincreasing the contacted surface area in such instances.

To produce these desirable end results, it is preferred that theexterior surface of the outer envelope or sheath deviate from the meansheath thickness by about between 8 and 20 percent. This, in effect,further defines the respective dimensions of the nodular protrusions andvoids therebetween. The novel plastic or resin covering or sheath alsorestrains and retains fragments of the glass receptacle should suchreceptacle be broken even when the container is pressurized toconditions approximating sixty pounds per square inch. This effect isproduced in accordance with the invention, by providing the plasticcovering or sheath of a flexible, resilient resin which will stretch andexpand rather than itself fragment in the event of receptacle failure.Such expansion of the covering before its own failure enables glassfragments to be restrained until the pressure within the receptacleescapes through initially formed, relatively small openings or fissureswhich may appear in the covering or sheath as it fails or until thepressure is otherwise relieved.

FIG. 1 is a front elevational view of a container of the preferredembodiment;

FIG. 2 is a partial cross-sectional view of the container shown in FIG.1 along line A-A thereof which illustrates prior art construction; and,

FIG. 3 is a partial cross-sectional view of the container shown in FIG.1 along line AA thereof illustrating the invention.

In the preferred embodiment of the invention, container I as shown inFIGS. 1 and 3 comprises an inner glass receptacle or envelope l2 and anexterior outer sheath or envelope l4 comprised of a flexibleshaperctaining resin contiguously covering a majority of the exteriorsurface 16 of receptacle [2. Sheath 14 is provided on its outer exposedsurface 18 with a plurality of preferably randomly positioned outwardlyextending shock absorbing nodes 20. These nodes are separated bydepressions 22 which are believed to permit maximum deflection andexpansion of nodes in a direction parallel to surface 16 upon receipt ofexcessive impacts. Accordingly, this maximized deflection is believed toincrease the shock absorbing characteristics of sheath l4 and inaddition, reduces the amount of material needed for an effective shockabsorbing sheath 14, thus reducing the cost of manufacturing container10.

In the preferred embodiment, inner glass receptacle or envelope 12 has awall thickness (Gx) of from about 0.03 to about 0.12 inches and theouter envelope 14 has a thickness of from about 0.004 to about 0.018inches. This outer envelope preferably also is formed so that specificdimensional qualities are maintained. For example, it is consideredideal to provide a mean envelope thickness value (Px) of about between0.008 and 0.0l2 inches. Similarly, it is preferred that the nodes andvoids have a mean deviation above and below this base value on the orderof 12 to 18 percent and approximately 8 to 12 percent respectively. Inother terms, it is found that the preferred maximum nodular elevationabove the mean thickness value varies between 6 and 60 percent and thatmaximum deflection of the voids below the mean thickness value variesbetween about 20 and 40 percent.

PREFERRED SHEATl-I OUTER SURFACE It should be obvious that this surfaceconfiguration substantially differentiates from that shown in FIG. 2where the outer envelope thickness (Pm) is virtually uniform andaccordingly is devoid of surface deviations as are described. Thus, asis indicated above, the coating thickness is not uniform throughout andthe maximum such thickness is created at the nodal areas 20; whereas ineach instance the thickness at depression 22 will be within the notedrange but less than at the nodes.

The material of construction of sheath 14 may be flexible and resilientresin which will stretch and expand rather than crack or fragment ifinner receptacle [2 should break whether or not it is under internalpressure. Thermosetting resins such as flexible crosslinked urethanerubbers or others may be used; however, thermoplastic resins arepreferred since they can be formed into coatings and films more easilyand react in the manner above described and as is important in carryingout the invention.

Thermoplastic polymers of butadiene, acrylates, ethylene, propylene,styrene, vinyl, chloride, vinyl acetate, cellulose acetate, cellulosebutyrate and cellulose propionate may be used. In addition,fluoroplastics, methyl pentenes, polyamides, phenoxy resin,polycarbonates, polyamides, polyphenylene oxides and polysulfone may beused.

The preferred plastics are inexpensive, have a relatively high tearstrength, have high impact resistance, easily form a contiguous film orcoating and are flexible. Of those above mentioned, the preferredplastics are polyethylene, acrylonitrile-butadiene-styrene copolymersand impact polystyrene.

It is, of course, appreciated that a suitable means of application ofthe coating material or sheath 14 to inner glass receptacle 12 is anecessity and as examples it is suggested that any of the following maybe employed depending upon the manufactures desired:

a. By spraying the the thermoplastic material as a powder, optionally byan electrostatic spraying method, onto the hot external surface of theinner receptacle;

b. By dipping the inner receptacle, maintained at an appropriatetemperature, into a fluidized bed of the plastic material in powderform;

c. By dipping the inner receptacle, if desired while hot, into a moltenboth of the plastic material or into a solution or a dispersion of suchmaterial, or

d. By any other method of providing a sleeve type coating to an innerglass receptacle known in the art.

I claim:

1. A shatter-resistant composite bottle having base means, side wallsand a neck portion comprising a pressurizable inner glass envelopehaving a mean side wall thickness of between about 0.030 inches and0.120 inches and a thermoplastic resin outer envelope of a meanthickness of between about 0.004 inches and 0.018 inches surrounds saidinner envelope and ex tends over substantially the entirety thereof saidouter envelope being further characterized in that its exterior surfaceis randomly nodularly configured and has a mean deviation value of about12 and l8 percent above that of the outer envelope thickness and a meandeviation value of about between 8 and 12 percent below that of theouter envelope thickness.

2. A shatter-resistant composite bottle comprising an inner glassenvelope having a mean sidewall thickness of between about 0.030 inchesand 0.120 inches and an outer envelope of a thermoplastic materialhaving a mean thickness of between about 0.004 inches and 0.018 inchesextends over substantially the entirety of said inner glass envelopeexcepting the finish thereof, the exterior surface of said outerenvelope being further characterized in that it is nodularly configuredand has a maximum elevation above said mean varying between about 6 and60 percent thereof.

3. A shatter-resistant composite bottle according to claim 2 whereinsaid outer envelope is additionally characterized in that its maximumdeflection below said mean thickness varies between about 20 and 40percent thereof.

1'' it l

1. A shatter-resistant composite bottle having base means, side wallsand a neck portion comprising a pressurizable inner glass envelopehaving a mean side wall thickness of between about 0.030 inches and0.120 inches and a thermoplastic resin outer envelope of a meanthickness of between about 0.004 inches and 0.018 inches surrounds saidinner envelope and extends over substantially the entirety thereof saidouter envelope being further characterized in that its exterior surfaceis randomly nodularly configured and has a mean deviation value of about12 and 18 percent above that of the outer envelope thickness and a meandeviation value of about between 8 and 12 percent below that of theouter envelope thickness.
 2. A shatter-resistant composite bottlecomprising an inner glass envelope having a mean sidewall thickness ofbetween about 0.030 inches and 0.120 inches and an outer envelope of athermoplastic material having a mean thickness of between about 0.004inches and 0.018 inches extends over substantially the entirety of saidinner glass envelope excepting the finish thereof, the exterior surfaceof said outer envelope being further characterized in that it isnodularly configured and has a maximum elevation above said mean varyingbetween about 6 and 60 percent thereof.
 3. A shatter-resistant compositebottle according to claim 2 wherein said outer envelope is additionallycharacterized in that its maximum deflection below said mean thicknessvaries between about 20 and 40 percent thereof.